Active Network Management (ANM)
In areas where there are multiple complex constraints affecting a number of customers over a long time period, an Active Network Management (ANM) system will be implemented. Distributed control systems continually monitor limits on the network and then allocate the maximum amount of capacity to customers in that area based on the date their application was submitted. This Last In, First Out (LIFO) hierarchy prioritises the oldest connections when issuing capacity, but is scalable so that new entrants will get access to the capacity when it becomes available.
Where constraints are driven by NGED limits they may be referred to as Distribution Active Network Management (DANM) and for National Grid constraints Transmission Active Network Management (TANM). TANM may cover either SGT Reverse Power Flow or the Technical Limit for a GSP, whichever is lower. Both DANM and TANM constraints are handled by the same ANM systems per zone. Where TANM is used to manage a constraint all connections within the GSP will be required to be controlled by that system. Where constraints exist on NGED’s distribution network the option to pay for reinforcement or to connect using DANM will be given to the customer. Upon application an assessment will be carried out to determine whether a Flexible Connection or Curtailable Connection (in line with DCUSA Schedule 2D) should be issue based on the Minimum Scheme for the application.
More detail of how NGED’s ANM system works and the requirements for connections using it can be found in the NGED Active Network Management Guidance document.
When issuing an offer for a Curtailable Connection, NGED will provide a Curtailment Limit in line with the requirements of DCUSA Schedule 2D. For all other offers that are subject to ANM NGED are currently undertaking a consultation to identify the most suitable approach for curtailment analysis.
ANM Zone roll out
NGED are rolling out new ANM zones based on the estimated energisation dates of new connections.
Additional costs associated with ANM
NGED have fully integrated the communication paths and control mechanism of their ANM system within its existing infrastructure. All EHV connections to the network require a Connection Control Panel to be installed at the DNO/Customer boundary, which can be configured for a site using ANM.
In order to instruct and police the applied ANM set point, suitable communications infrastructure and a fully rated circuit breaker are required and cost in the region of £32,000 (typical cost in September 2020). These are not required as standard for a connection below 33kV.
NGED use ANM to monitor constraints across various voltage levels, starting from the transformers feeding primary substation (at 11kV) up to the National Grid interface (at 400kV). Sites as small as 500kW on the 11kV network are eligible to use ANM. The granularity of curtailment, availability of supply of equipment and cost of the required equipment will limit any sites smaller than this.
When a connection is looking to energise on our network using ANM a charge of up to £15,000 is required to cover the cost of commissioning and testing the ANM system.
TANM and Appendix G
As part of NGED interaction with National Grid information is supplied on the level of generation connected to the network. Please see the TANM and Appendix G page for detail on the difference between the two.
Other Load Management Systems
NGED are procuring demand response services using Flexible Power. Information on this and how to participate are available on the Flexible Power website.